1. Field of the Invention
The present invention relates to an automotive vehicle body having enhanced energy absorbing cross member augmentation.
2. Disclosure Information
Destructive testing of automotive vehicles typically includes the imposition of dynamic loading to the vehicle bodysides, typically in the form of a pendulum strike on the bodyside, or by crash testing. Such testing, in either form, imposes severe loading on the structural members of the body. The inventor of the present structural system has determined that the ability of the body to manage such laterally directed loads will be enhanced with the addition of an energy management device described herein. The present device allows the vehicle""s body cross members to react in a more controlled manner against laterally imposed loads, and at an earlier time during a crash sequence, because the deformation of the body will result in column loading of the underbody cross members at an earlier time than was previously the case. Although automotive bodies used in conventional body-on-frame construction have typically used cross members for decades, such cross members have not been involved in the management of crash related energy in the manner of the augmented cross members described herein. In essence, with a more typical construction, the space between the inner rocker panel and the end of the underbody cross members must first be closed by plastic deformation of the sheet metal bridging between these two structures. This sheet metal is usually flat and comprises a portion of the floorpan. The present invention provides much greater energy absorption during this stage of the bodyside deformation by providing the capability for column deformation of the present inventive structures, as well as the cross members, rather than mere bending of flat sections of sheet metal.
According to the present invention, an automotive body includes an outer rocker panel, an inner rocker panel joined to the outer rocker panel, a floor pan joined to the inner rocker panel, and at least one cross member extending laterally across a portion of the body, with the cross member being joined to the floor pan. The present inventive system also includes a cross member extension interposed between an outboard end of the cross member and the inner rocker panel. The cross member extension preferably has a first end welded to the inner rocker panel and a second end welded to either the cross member itself or to a vertically extending portion of a lower floor pan. In the latter case, the cross member will itself be welded to the vertically extending portion of the lower floor pan.
An automotive body according to present invention may preferably comprise either a welded steel structure or a plastic composite structure, or combinations thereof. For example, a cross member extension according to the present invention may comprise either high strength plastic or foam, or other plastic or fiber reinforced plastic composites, or carbon fiber, or stamped steel or aluminum, or other metallic and non-metallic materials known to those skilled in the art and suggested by this disclosure.
A cross member extension according to the present invention may fill the entire gap extending between an lower floor pan and an inner rocker panel; alternatively, the cross member extension may have a relieved portion permitting the passage of conductors through the vehicle body in a direction generally parallel to the inner rocker panel. The cross member extension may comprise either a downward opening channel, or a complete box section. Further, the cross member may comprise an upward opening channel having flanges joined to the floor pan by bonding, welding or other methods known to those skilled in the arts and suggested by this disclosure.
An automotive body according to the present invention preferably comprises a plurality of cross members with each having cross member extensions aligned with the ends of the cross members at each end of the cross members. In other words, it is contemplated that two cross member extensions will be associated with a plurality of cross members in an automotive body constructed according to the present invention.
According to another aspect of the present invention, a method for reacting to an impact load imposed laterally on a passenger door of an automotive body includes the steps of reacting to the load initially with plastic deformation of the door, followed by reacting secondarily with plastic deformation of a rocker panel structure abutting the door, in response to loading imposed upon the rocker panel structure by the door, and finally, reacting to the load with column compression and buckling of the cross member and a channel-shaped cross member extension in response to loading imposed upon the cross member extension by the rocker panel structure.
It is an advantage of the present invention that the present cross member extension structure allows an automotive body to react to higher loads with more controlled plastic deformation of the body structure.
Other advantages, as well as objects and features of the present invention, will become apparent to the reader of this specification.